KSAZ/ABC News(PHOENIX) -- A gunman shot and wounded three people at an office building in Phoenix on Wednesday and police are now searching for the shooter, authorities told ABC News.

One of the victims is in critical condition; the others received non-life threatening injuries, according to police.

Officials say there was only one gunman, who remains at large.

A witness told ABC News she heard several shots, and took cover in an IT closet with several other women. Another witness heard between six and 10 shots fired.

Police believe the suspect entered the building looking for a specific individual, but was confronted and an altercation ensued, Phoenix police Sgt. Tommy Thompson told ABC News affiliate KNXV-TV.

Cops know the name of the suspect and are at his home.

In addition to the office complex, and the suspect's home, police are also investigating a third scene, according to KNXV-TV. It's not clear how it's related to the office shooting.

The shooting took place moments after former Arizona congresswoman Gabrielle Giffords, the victim of a shooting in Phoenix in 2011, testified before Congress on gun control.

In the weeks since 20 students were gunned down at a Newtown, Conn., elementary school on Dec. 14, 2012, several mass shootings have garnered public attention as the nation debates its relationship to firearms.

Five days ago, two men were wounded during a shooting at Lone Star College in Houston, Texas. Earlier this month, a 16-year-old student was arrested after shooting a classmate in Taft, Calif.